Characterization and stability evaluation of beta-carotene nanoemulsions prepared by high pressure homogenization under various emulsifying conditions

In this study, oil-in-water nanoemulsions of P-carotene were produced by high pressure homogenization. The influence of emulsifying conditions including emulsifier type and concentration, homogenization pressure, temperature and cycle on the properties and stability of the nanoemulsions were investigated using a Zetasizer and a Turbiscan Lab, respectively. The mean diameters (z-average) of the dispersed particles containing P-carotene ranged from 132 to 184 nm and the size distribution was unimodal and extended from 40 to 400 nm. The nanoemulsions produced with Tween 20 had the smallest particle sizes and narrowest size distribution. The particle sizes decreased with increases in homogenization pressure and cycle, and also with temperature up to 50 degrees C. The physical stability of the nanoemulsions decreased with the elevation of temperature but increased with pressure (up to 100 MPa) and homogenization cycle (up to three cycles). During storage at 4 degrees C and 25 degrees C, up to 25% of P-carotene in the nanoemulsions was degraded after four weeks with slightly greater loss occurred at 25 degrees C. (c) 2007 Elsevier Ltd. All rights reserved.